Electrical condenser and method of making the same



27, 1929- H. I. DANZIGER 1,726,343

ELECTRICAL CONDENSER AND METHOD OF MAKING THE SAME Filed Aug. 27, 1927 Fig.1.

INVENTOR. Harold Donzlger Patented Aug. 27, 1929.

HAROLD I. DANZIGER, OF NEW YORK, N. Y.

ELECTRICAL CONDENSER AND METHOD OF MAKING THE SAME.

Application filed August 27, 1927. Serial No. 215,787.

Mypresent invention relates generally to the manufacture of electrical condensers, and has particular reference to the type of con densers wherein layers of foil and insulating 5 material are interwound in alternate relationship.

In the manufacture of this type of condenser, it is customary to employ a suitable type of paper for the insulatlng layers, and

1 to subject the interwoun-d assembly to heat and vacuum treatment and then .to an impregnation treatment whereby a dielectric material of far greater dielectric strength than that of the paper will find its way between the foil layers. Where the dielectric material employed is wax or the like, it is customary to press the interwound assembly into a flat body, and then to subject these flattened bodies to the'heat and vacuum and impregnation treatment by placing them into a rack or other suitable support and inserting the rack into the treatment chamber. Where oil or the like is employed as the dielectric material, the pressed roll is generally inserted into a suitable individual container which is left open and which is then inserted into the treat-V ment chamber so that the oil will eventually find its way into the container.

The foregoing steps, are not directly in-' volved in the present invention, but are described in this brief way for the reason that my present invention 'does not substantially alter the general nature of this manufacturing process.

In each of the foregoing illustrations, it is the wax or the oil which serves as the primary dielectric; the paper being necessarily employed to permit the interwinding to be effected and to retain the foil strips in insulated relationship prior to and during the impregnating procedure. It is accordingly extremely desirable to effect a thorough impregnation. In fact, in an ideal condenser, no paper would be present at all in the completed condenser. 1

It is one object of the present invention to provide a condenser, and a method of manufacturing the same, wherein and whereby the thickness of the layer of oil, wax, or similar creased, and wherein and whereby the relachief dielectric material, is substantially 'intive amount of paper is at the same time re- A coordinate object of my invention is to provide an improved insulating layer or strip, and a method of manufacturing the same for subsequent employment in the manufacture of electrical condensers according to well known processes.

It is a feature of my invention to provide an insulating strip which comprises two layers of the usual insulating paper, in combination with means for retaining these layers in separated or spaced relationship while at the same time rendering said space available for the accommodation of the chief dielectric material subsequently to be applied. More particularly, the spacing means last referred to comprises a sandwich spacing layer or strip.

A preferred construction employs a mesh layer or strip of considerable coarseness, as

the spacing strip referred to. A continuous strip of suitable textile material for example, is not only absorbent, but easy to handle in roll form.

Another feature of my invention lies in the suitable preparation of the san-dwiching strip, including heat and vacuum treatment, prior to its association with the paper strips. The preparation involves the application of an adhesive to the outer surface of the sandwiching strip, and it is a feature of my invention to apply this adhesive to the outer surfaces only, without filling in the interstices betweenthe mesh.

A further feature of my invention resides in the employment of wax as the adhesive referred to. In this way, the subsequent employment of wax as a dielectric will be particularly feasible in that the subsequently applied wax will merge with the coatings used as adhesive and will thereby'provide a resultant insulating layer of great efiiciency.

For the attainment of the foregoing objects and such other objects as may herein- 'trated one form of my inventlon in the acco p y ng draw g in which- Fig. 1 is a diagrammatic representation of the steps involved in the preparation or manufacture of my improved insulating strip;

Fig. 2 is a greatly enlarged cross-section taken substantially along the line 22 of Figure 1;

Fig. 3 is a diagrammatic perspective view of the steps involved in the winding of the condenser body; and

Figure 4 is a perspective view of a completely Wound and compressed condenser body.

10 represents a continuous strip of relatively coarse perforated material, such as a coarsely woven textile material or the like. 11 and 12 represent rolls of continuous strips of paper, preferably of the character usually employed in the manufacture of condensers. The strip 13 leading from the roll 10 is guided into sandwiched relationship with the strips 14 and 15 leading from the rolls 11 and 12 respectively. Prior to the actual sandwiching of these three strips between the sandwiching means represented diagrammatically by the rollers 16, the strip 13 is coated on opposite surfaces by a suitable adhesive. I have represented the application of this adhesive diagrammatically by illustrating two adhesive reservoirs 17 and two rollers 18 and 19 designed to apply the adhesive to the opposite surfaces of the strip 13 respectively. 20 represents a roll of the completed composite insulating layer or strip.

In Figure 2 the cross-sectional nature of this completed composite strip is shown. It

will be noted that the paper layers 14 and 15 are retained in spaced relationship, and that the interposed or sandwiched mesh layer 13 embodies a perforated nature which permits the space between the layers 14 and 15 to accommodate a considerable amount of dielec-' tric material ultimately to be applied.

Before proceeding to describe the subsequent steps involved in the manufacture of completed condensers, I wish to point out that the strip13, before the association there-.-

of with the strips 14 and 15, is advantageously subjected to heat and vacuum treatment to effectually expel all entrained moisture and air, if any. I wish to point out further that the mechanism disclosed in Figure 1 is purely diagrammatic. For example, I have found it desirable to employ the ordinary dielectric wax as a suitable adhesive. And I have found it satisfactory to insert the entire roll 10 into the usual heat and vacuum chamber, thereupon subjecting the roll to such treatment and then impregnating it with the wax.

Subsequently, when the strip 13 is associated with the paper strips, it will be found to be suitably dried and also satisfactorily coated on opposite surfaces with a very thin layer of hardened wax. It will be understood that this coating of wax is one which serves merely the function of an adhesive. It is preferable that the wax does not fill in the perforations of the mesh, for if the composite insulating strip is subsequently employed in oil-impregnated condensers, these perforations must be free to accommodate the oil.

In the preferred method just described, wherein a thin coating of wax is employed as the adhesive material, the rollers 16. or their equivalents, are provided with means for applying not only pressure but heat to the layers being sandwiched thereby. In this way, the thin layer of wax is momentarily heated to a suflicient degree torender it liquid, and the hardening of the wax thereafter results in the provision of a completed composite insulating strip of extremely efiicient characteristics.

The reason I prefer to employ wax as the I adhesive instead of any other ordinary adhesive (although the latter would be quite satisfactory), is that wax has a decidedly high dielectric constant which may not necessarily be embodied in an ordinary adhesive.

The composite strip is of course merely typical of a plurality of such strips which may be independently prepared for employment in the manufacture of condenser bodies. In Figure 3 I have illustrated one method of employing two such composite'strips in the formation of a condenser body. 21 and 22 represent rolls of .my composite insulating strips. 23 and 24 represent rolls of foil, preferably of the character usually employed in the manufacture of condensers. The strips 25, 26, 27, and 28, leading respectively from the rolls 2124, age interwound in alternate relationship upon a suitable mandrel 29. It will be noted that the insulating strips 25 and 26 are in substantial alignment with each other in the interwound assembly, whereas the foil strip 27 extends outwardly beyond one-edge of the insulating strips and the foil strip 28 extends outwardly beyond the opposite edge of the insulating strips. be noted that the opposite edges of the foil strips 27 and 28 are themselves overlapped by the insulating strips. In this way, a com-- Furthermore, it will pleted interwound assembly such as that.

opposite end portion 31 comprises superposed edges of, the other foil strip (for example, strip 28) these end portions being completely insulated from each other and being therefore usable as terminals in the completed condenser. Usually a pair of contact terminals or strips 32 and 33 are made to project outwardly from the end portions 30 and 31. In Figure 4 I have" also'shown a sticker or label 34 applied to the free ends of the insulating strips. 25 and26 to hold the condenser body in wound condition.

Although the condenser body need not necessarily be wound in the manner diagrammatically shown in Figure 3, I have found present invention, and the same is true of the particular type of dielectric material employed as the impregnation material.

be pointed out, however, that the composite insulating strip renders the heat and vacuum treatment particularly efficient because of the accessibility of the heat and the vacuum to the innermost portions of the paper strips. Also, where wax has been employed as the adhesive, the employment of wax as the impreg-- nating material is particularly efficient. It will be understood, however, that oil or other suitable dielectric may be employed if desired.

It will be understood that although I have herein described and diagrammatically illustrated the employment of a literally perforated material such as mesh, nevertheless in View of the function of such a layer as pointed out herein, the term perforated will be understood to include within its meaning any material or layer which has a relative amount of bulk and which is at the same time extremely absorbent and capable of ac commodating a dielectric material. For example, I have found it satisfactory to provide an insulating layer or strip made up of two outer layers of paper (of the character herein described), and a sandwiched layer of relatively thick yet unsized and highly absorbent paper. Similarly, a material such as absorbent cotton might be employed, although the ununiform thickness of such a material renders it slightly more unsatisfactory for the present purpose than the other types of material herein mentioned.

It will also be understood that although I have described and illustrated a method and construction wherein a single piece of perforated material is sandwiched between two pieces of unperforated material, nevertheless it is quite feasible, where additional thickness is desired, to employ additional layers of perforated and unperforated material. Thus, I have found it satisfactory to employ a five-ply insulating layer consisting of three paper strips and two mesh strips arranged in alternate relationship. It may also be found satisfactory to sandwich a paper strip between two mesh strips, and in general I do not mgan to limit myself to any particular mutual arrangement or number of perforated and unper orated layers.

It will be obvious that changes in the details herein described and illustrated for the purpose of explaining the nature of my invention. may be made by those skilled in the art without departing from the spirit and pended claims.

It may scope of the invention as expressed in the ap- It is therefore intended that these details be interpreted as illustrative and not in a limiting sense.

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent is 1. The herein described method of making an insulating strip for electrical condensers, which comprises the steps of subjecting a perforated strip of material to heat and vacuum treatment so as to dry the latter, applying wax to only the opposite surfaces of said strip,

and sandwiching said strip, under heat and pressure, between two unperforated strips of material.

2. The herein described method of making an insulating strip for electrical condensers, which comprises subjecting a continuous strip of mesh to heat and vacuum treatment to dry the latter, subjecting said'strip to molten wax to coat the opposite surfaces thereof, guiding the coated strip into sandwiched relation with two continuous strips of unperforated paper, and applying heat and pressure to the strips to cause adherence therebetweenand thereby produce a composite strip when the wax has cooled.

3. A composite insulating layer of the character described, comprising a layer of perforated material sandwiched between layers of unperforated material, whereby the latter are retained in spaced relationship and whereby said space is adapted to accommodate dielectric material.

4. A composite insfi lating layer of the character described, comprising a layer of mesh adhesively sandwiched between layers of paper, whereby the latter are retained in spaced relationship and whereby said space is :irdapted to accommodate dielectric materia 5. In an electrical condenser, a composite insulating layer sandwiched between layers of conducting material, said composite layer comprising a layer of perforated material sandwiched between layers of unperforated insulating material.

6. In an electrical condenser, a composite insulating layer sandwiched between layers of foil, said composite layer comprising a between layers of tionship and whereby said sandwiched layer is adapted to absorb and thereby accommodate a dielectric material.

9. A composite insulating layer of the character described, comprising a plurality of alternately arranged layers of perforated and unperfor'ated material.

10. An electrical condenser comprising a set of alternately arranged conducting and insulating. layers, the insulating layers comprising a compositelayer made up of alternately arranged perforated and unperforated layers.

,11. A composite insulating material of the character described, comprising alayer of relatively absorbent and relatively bulky material sandwiched between layers of relatively dense material, adhesive material attaching the outer layers to the inner layer, substantially all of said adhesive material being at the surfaces of the layers whereby the outer layers are retained in spaced relationship and the inner layer retains its absorbent characteristics.

12. A composite insulating material of the character described, comprising a layer of relatively absorbent and relatively bulky material sandwiched between layers of paper, adhesive material attaching the outer layers to the inner layer, substantially all of said adhesive material being at the surfaces of the layers whereby the outer layers are retained in spaced relationship and the inner layer-retains its absorbent characteristics.

13. An electrical condenser comprising a set of longitudinally arranged conducting and insulating layers, the insulating layers consisting of a composite material comprising a layer of relatively absorbent and relatively bulky material sandwiched between layers of relatively dense material, adhesive material attaching the outerlayers to the inner layer, substantially all of said adhesive material being at the surfaces of the layers maasee whereby the outer layers are retained in spaced relationship and the inner layer retains its absorbent characteristics.

14. An electrical condenser comprising a set of longitudinally arranged conducting and insulating layers, the insulating layers consisting of a composite material comprising a layer of relatively absorbent and relatively bulky material sandwiched between layers of paper, adhesive material attaching the outer layers to the inner layer, substantially all of said adhesive material being at the surfaces of the layers whereby the outer layers are retained in spaced relationship and the inner layer retains its absorbent characteristics.

15. An electrical condenser consisting of the structure described in claim 13 and having dielectric material absorbed in the ab sorbent material.

16. An electrical condenser consisting of the structure described in claim 14 and having dielectric material absorbed in the obserbent material.

17. A. composite insulating material of the character described, comprising a layer of relatively absorbent and relatively bulky material sandwiched between layers of relatively less absorbent and less bulky material, whereby the outer layers are retained in spaced relationship and the inner layer is adapted to absorb dielectric material.

,18. An electrical condensercomprising a set of longitudinally arranged conducting and insulating layers, the insulating layers con sisting of a composite material comprising a layer of relatively absorbent and relatively bulky material sandwiched between layers of relatively less absorbent and less bulky material, whereby the outer layers are retained in spaced relationship and the inner layer is adapted to absorb dielectric material.

In witness whereo'r', I have signed this specification this 25 day of August, 1927.

. HAROLD l. DANZIGER. 

